Re: I/O streaming with custom data transport

[Robert A Duff <bobduff@shell01.TheWorld.com>]

Maciej Sobczak <no.spam@no.spam.com> writes:

>    procedure Write_Hello(Stream : in out Stream_Access) is
>    begin
>       String'Write(Stream, "Hello");
>    end Write_Hello;

I don't understand this.  Ada streams are streams of Stream_Elements
(usually bytes), and the 'Read/'Write attributes encode things in
some way that is not necessarily human-readable.  For example,
I think the above outputs the bounds of the string in some
binary form.

But the original question was about streams of characters,
intended to be human-readable.  Right?

So how do Ada's streams help, here?

It seems to me what you want is an abstract Character_Output_Stream
type, with a primitive (or class-wide?) operation that puts a Character
to the stream.  Then you can make derived types for sending to a file,
to an in-memory buffer, etc.

- Bob